This might be hard to do with a load-balancer setup alone, because the balancer would need to know when to fail over (and not just in the case of Zope stopping to respond); another similar solution might be more along the lines of IP takeover software like Heartbeat (linuxha.org) or Failsafe (oss.sgi.com) that makes the "safe" hot-backup Zope box takeover the identity of the "corrupted" primary Zope box, assuming that you have a monitoring setup on the backup to audit the integrity of your primary Zope service/data. The advantage that this has over a load-balancer approach is that you can write your own custom monitors/audit-scripts to determine/test the criteria for a failover to a much more fine-grained degree than just refused HTTP connections. Linux Failsafe has service monitoring setups, while you would use Mon or something similar in conjunction with Heartbeat. I would suggest a combination of Squid in front and heartbeat or Linux Failsafe on Zope boxes (either independent ODB or with ZEO) nodes in this case. You could use ZEO+ExternalMount or ZSyncer to copy content to your second Zope if you had 2 antonymous Zopes. Squid (or any other reverse-proxy or load-balancer) would then obey any IP address takeover from a hot-backup node happening via gratuitous/unsolicited ARP. Sean -----Original Message----- From: Anthony Baxter [mailto:anthony@interlink.com.au] Sent: Monday, January 21, 2002 4:18 PM To: Terry Hancock Cc: zope@zope.org Subject: Re: [Zope] Static fail-over
Terry Hancock wrote I have a Zope site which I'm doing a lot of development on, and all internal safeguards aside, I feel there's a significant chance of wrecking Zope in the process. Then it might take anywhere from hours to days to get it back up again.
Aside from making sure you have a sane development and deployment process, you could consider using a load balancer, set up to point to the primary (development?) server normally, and switching it to a backup one when things fail. There's a bunch of hardware or software ones - I've used both. Hardware's better, obviously, but you could consider something like the tool 'balance' from balance.sf.net Anthony _______________________________________________ Zope maillist - Zope@zope.org http://lists.zope.org/mailman/listinfo/zope ** No cross posts or HTML encoding! ** (Related lists - http://lists.zope.org/mailman/listinfo/zope-announce http://lists.zope.org/mailman/listinfo/zope-dev )